1. Field of the Invention
The present invention relates to an introduction aid for stretching a guide wire, in particular a Seldinger wire with a flexible tip which is curved in a J shape, and securing the guide wire in a dispenser tube and to a connection element for connecting the introduction aid to the dispenser tube.
2. Description of Related Art
Used for introducing a single-lumen or multi-lumen catheter into a blood vessel is a guide wire which is brought through a puncture point to the target site and over which subsequently the catheter is advanced. This is called the Seldinger technique, which is performed using a Seldinger wire which is distinguished by a highly flexible tip which is curved in a J shape. Since guide wires may have a considerable length (0.4 to &gt;1 m) and, apart from the highly flexible tip, have a certain elastic stiffness, the user is impeded by the end of the guide wire which projects freely out of the patient's body, and it is important to keep this end in the form of a loop. For this purpose, and for the purpose of transport, the guide wire is accommodated in a rigid dispenser tube which is converted into a coil and kept in this shape, and from which it can be released into the patient's body through an introduction kit. The dispenser tube which is converted into a coil is normally kept in place with the aid of separate clips which have longitudinal slits and are designed as double or triple clasps and in each case clamp together adjacent tube strands. The dispenser tube consists of a solid plastic, for example polypropylene, and its internal diameter is larger than the external diameter of the guide wire so that the latter slides very smoothly in the lumen of the tube. In this case, the J-shaped tip of the guide wire is stretched using an introduction aid at the junction between the end of the dispenser tube and the inlet of the catheter kit, for example a needle attachment. The introducer is provided with a pipe whose internal diameter is only slightly larger than the diameter of the guide wire so that the J-shaped tip is stretched straight. In the packaged state, the J-shaped tip of the guide wire projects beyond the front opening of the channel of the pipe so that the curvature retains its original radius and is not fatigued during the storage time due to permanent stretching in the pipe. One problem which arises is that the guide wire which slides smoothly in the dispenser tube may slip out of the dispenser during transport, which results in kinking in the packaging.
German utility model 93 19 838.8 describes an introduction aid for catheter guide wires which solves this problem. It discloses a device for securing and stretching the ends of guide wires, which comprises an elongate hollow element open at both ends, with a cylindrical section and a conical section which tapers towards the end, with a U-shaped slit extending in the longitudinal direction being present in the wall of the hollow element, so that a tongue which can be pressed into the inside of the hollow element is formed between the legs of the U-shaped slit open towards the end. A clamping fit of this device on the dispenser tube is achieved by the device being pushed onto the tube until the tongue is situated in the inside of the tube and, by means of the spring action, fixes the end of the tube in the cylindrical section of the device. The tongue, which in this way is pressed further inwards, secures the catheter guide wire against displacement in the longitudinal direction. In order to be able to introduce the J-shaped tip of the guide wire into a needle, the user must hold the dispenser tube with one hand and use the other hand to grip the introduction aid and pull it out of the end of the tube. The user must then use the hand holding the dispenser tube additionally to grip the guide wire and, with the other hand, pull the introduction aid over the J tip so that the J-shaped end is stretched in the introducer. After this, the user introduces the introduction aid with completely retracted guide wire into the attachment of the needle which has already been used for puncture. While he holds the introducer and end of the needle with one hand, he is able to advance the guide wire into the vein with the other hand. This manipulation is relatively involved because the user always requires both hands.
The dispenser disclosed in U.S. Pat. No. 5,125,906 did not have this disadvantage and is distinguished by being amendable to operation with one hand. This is attributable to the fact that an axial section of the introduction aid between a sleeve-like connection part with a closed wall for the dispenser tube and the pipe for stretching the J-shaped tip is bridged by an advancing surface and is open to the outside so that a finger or the thumb of the hand holding the introduction aid can be used to displace the guide wire crossing the axial section. A handle is located on the underside of the axial section bridged by the advancing surface, in order to facilitate operation by the user with one hand, and the end of the handle has a clamp for fastening the proximal end of the dispenser tube. The pipe channel and the guide wire passage are arranged coaxially, resulting in the guide wire being displaceable smoothly and without inhibition, which may lead to the guide wire slipping out in an unwanted manner during transport.
A dispenser which has an introduction aid and which can be operated with one hand and, at the same time, secures the guide wire against unwanted slipping out is described in European published specification 587 984. The introduction aid disclosed therein differs from that in U.S. Pat. No. 5,125,906 in that the longitudinal axes of the guide wire passage of the connection part and of the channel of the pipe, which is provided at an axial distance therefrom, for stretching the J-shaped tip run in planes which are offset with respect to one another, resulting in a self-inhibiting effect for the guide wire which is accommodated in the dispenser tube which is converted into a loop, which is intended to prevent the wire slipping out or to one side during storage and transport. However, it has emerged in practice that the offsetting is insufficient in fact to stop the wire slipping out. Just like the introduction aid from U.S. Pat. No. 5,125,906, the introduction aid described in European published specification 587 984 also not only grips at the distal end of the dispenser tube but likewise has a clamp or a clip which is fastened at the proximal end of the dispenser tube or, in the case of longer tubes, on the middle region thereof.
U.S. Pat. No. 5,282,479 relates to another introduction aid which can be operated with one hand and has transport securing. The introduction aid has at its proximal end at least two flexible lugs whose total extent in the unbraced state is greater than the internal diameter of the dispenser tube and which are forced into the dispenser tube. The guide wire is thus clamped firmly between the lugs in order to prevent the wire slipping out during transport. The dispenser tube has at its distal end a number of openings which corresponds to the number of flexible lugs, into which openings the lugs engage on use of the introduction aid after rotation thereof, and relax and release the guide wire so that the latter can be pushed out of the dispenser. Another opening in the form of an elongate slit is located in the dispenser tube itself and permits the user not only to release the transport securing with one hand but also to advance the wire out of the dispenser. The disadvantage in this case is that, during fabrication, the dispenser tube must itself be altered, which is associated with additional industrial complexity.